The goal of the project is to develop the first disease-modifying, non-hormonal therapeutic for endometriosis (EMS). EMS is considered the greatest overlooked epidemic in women's health, affecting approximately 10% of women worldwide. It is the number one cause of infertility and disability among adolescents and women across all ethnicities. Shockingly, to date, there is no cure for this chronic and prevalent disease. Because it takes an average US woman 6?10 years to be diagnosed with EMS, the current management protocols of hormonal, pain therapies, or surgical interventions?which fail to reverse the disease or address the root cause?are often insufficient. Hormone pills and GnRH antagonists (causing ?medical menopause?) prescribed to patients with EMS can induce many undesirable side effects. Many women who undergo EMS excision will have reoccurrence within 5 years of surgery. Hysterectomies are recommended for women who do not experience relief through less invasive methods. Our team has developed a novel therapeutic option for EMS by targeting a downstream component of a pathway known to contribute to endometriosis pathogenesis and endometrial migration and invasion. Our panel of macrocyclic peptides specifically inhibits this downstream component and shows success in cell potency and proliferation assays, reporter assays, serum stability, membrane permeability, toxicity mouse studies, and exhibits great potential to act as an endometriosis therapeutic. Other molecules targeting the pathway have reversed EMS progression in academic settings, but have off-target or upstream pathway targets that induce undesired side effects. In this novel project, we will identify the most promising 2 macrocyclic peptides that inhibit the migration and invasion in EMS cells and confirm its efficacy in an EMS animal model. The compounds will be evaluated for cellular potency, PK/PD, on-target effects, confirm lack of off-target effects, inhibition of cellular invasion and migration, and efficacy using primary EMS cells donated by our collaborators at the Boston Center for Endometriosis. The cells have been excised from different patients and collected in accordance to the EPHECT standard protocols with accompanying clinical records. The PK, efficacy, and biodistribution of our macrocyclic peptides will also be evaluated an in vivo animal models of endometriosis, and on-target effects will be confirmed through qPCR of RNA, immunohistochemistry, and western blot analysis. Medicinal chemistry optimization will be performed on the lead candidate peptides to obtain an optimal clinical drug profile by becoming more unnatural, peptidomimetic (small molecule-like) agents. Once validated and optimized, these compounds will enter into preclinical investigation and toxicity studies in Phase II. These experiments will prepare us for a subsequent Phase IIB application to fund IND toxicity experiments in preparation for pre-discussions with the FDA as we prepare for an IND for Phase 1 clinical trials.